Transition metal nitride deposition method

ABSTRACT

The present disclosure relates to methods and apparatuses for depositing a transition metal nitride-containing material on a substrate in the field of manufacturing semiconductor devices. Methods according to the current disclosure comprise a cyclic deposition process, in which a substrate is provided in a reaction chamber, an organometallic transition metal precursor is provided to the reaction chamber in a vapor phase, and a nitrogen precursor is provided into the reaction chamber in a vapor phase to form a transition metal nitride on the substrate. The disclosure further relates to a transition metal nitride layer, to a semiconductor structure and a device, as well as to a deposition assembly for depositing a transition metal nitride on a substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 63/216,076 filed Jun. 29, 2021, titled TRANSITION METAL NITRIDEDEPOSITION METHOD, the disclosure of which is hereby incorporated byreference in its entirety.

FIELD

The present disclosure relates to methods and apparatuses for themanufacture of semiconductor devices. More particularly, the disclosurerelates to methods and systems for depositing metal nitride-containingmaterial on a substrate, and layers comprising a metal nitride.

BACKGROUND

Semiconductor device fabrication processes generally use advanceddeposition methods for forming metal-containing layers with specificproperties. Transition metal nitrides in groups 4 (titanium, zirconium,hafnium), 5 (vanadium, niobium, tantalum) and 6 (chromium, molybdenum,and tungsten) are potentially useful for a range of semiconductorapplications. In particular, these materials are proposed forback-end-of line (BEOL) barrier and liner applications, where lowelectrical resistivity is important. Additionally, many applicationsrequire low temperature deposition of these materials due to integrationthermal budget limitations, often 350° C. or less. Especially molybdenumnitride-containing materials are typically deposited in temperaturesthat are incompatible with BEOL applications.

Furthermore, methods that avoid fluorine (F) or chlorine (Cl) arepreferred over those that use these elements in the precursor orco-reactant. Unfortunately, most approaches that avoid F and CI arebased on metalorganic or organometallic precursors that contain carbon,which incorporates into the film in significant concentration and actsto increase the resistivity. The current invention provides a F-free andCl-free low temperature ALD route to low resistivity metal nitride filmswith low carbon content.

Any discussion, including discussion of problems and solutions, setforth in this section has been included in this disclosure solely forthe purpose of providing a context for the present disclosure. Suchdiscussion should not be taken as an admission that any or all of theinformation was known at the time the invention was made or otherwiseconstitutes prior art.

SUMMARY

This summary may introduce a selection of concepts in a simplified form,which may be described in further detail below. This summary is notintended to necessarily identify key features or essential features ofthe claimed subject matter, nor is it intended to be used to limit thescope of the claimed subject matter.

Various embodiments of the present disclosure relate to methods ofdepositing a transition metal nitride-containing material on asubstrate, to a transition metal nitride layer, to a semiconductorstructure and a device, and to deposition assemblies for depositingtransition metal nitride-containing material on a substrate.

In an aspect, a method of depositing a transition metalnitride-containing material on a substrate by a cyclic depositionprocess is disclosed. The method comprises providing a substrate in areaction chamber, providing an organometallic transition metal precursorto the reaction chamber in a vapor phase, and providing a nitrogenprecursor into the reaction chamber in a vapor phase to form atransition metal nitride on the substrate. In the method, the transitionmetal precursor comprises a transition metal from any of groups 4 to 6of the periodic table of elements.

In some embodiments, the transition metal precursor comprises a group 6transition metal according to the periodic table of elements. In someembodiments, the group 6 transition metal is selected from molybdenumand tungsten. In some embodiments, the group 6 transition metal ismolybdenum. In some embodiments, the transition metal precursorcomprises only molybdenum, carbon and hydrogen. In some embodiments, thetransition metal precursor comprises bis(ethylbenzene)molybdenum. Insome embodiments, the transition metal precursor comprises a benzene ora cyclopentadienyl group. In some embodiments, the nitrogen precursorcomprises only nitrogen and hydrogen. In some embodiments, the nitrogenprecursor is selected from a group consisting of NH₃, NH₂NH₂, andmixture of gaseous H₂ and N₂.

In some embodiments, the method according to the current disclosurefurther comprises providing an auxiliary reactant to the reactionchamber in a vapor phase. In some embodiments, the auxiliary reactantcomprises a halogen selected from a group consisting of bromine andiodine. In some embodiments, the auxiliary reactant comprises an organicgroup. In some embodiments, the auxiliary reactant comprises ahalogenated hydrocarbon. In some embodiments, the auxiliary reactantcomprises two or more halogen atoms. In some embodiments, at least twohalogen atoms being attached to different carbon atoms. In someembodiments, two of the halogen atoms in the auxiliary reactant areattached to adjacent carbon atoms of a carbon chain. In someembodiments, the auxiliary reactant comprises a 1,2-dihaloalkane or1,2-dihaloalkene or 1,2-dihaloalkyne or 1,2-dihaloarene. In someembodiments, the two halogen atoms of the auxiliary reactant are thesame halogen. In some embodiments, the auxiliary reactant comprises1,2-diiodoethane. In some embodiments, the auxiliary reactant is used toregulate the resistivity of the deposited transition metal nitridematerial.

In some embodiments, the auxiliary reactant comprises a group 14 elementselected from Si, Ge or Sn. In some embodiments, the auxiliary reactanthas a general formula R_(a)MX_(b) or R_(c)X_(d)M—MR_(c)X_(d), wherein ais 0, 1, 2 or 3, b is 4-a, c is 0, 1 or 2, d is 3-c, R is hydrocarbon, Mis Si, Ge or Sn, and each X is independently any ligand. In someembodiments, X in the auxiliary reactant is hydrogen, a substituted oran unsubstituted alkyl or aryl or a halogen. In some embodiments, thecyclic deposition process comprises a thermal deposition process.

In some embodiments, the cyclic deposition process comprises purging thereaction chamber after providing a transition metal precursor into thereaction chamber. In some embodiments, transition metal nitride isdeposited on the substrate as a layer.

In another aspect, a transition metal nitride layer produced by a cyclicdeposition process is disclosed. The method comprises providing asubstrate in a reaction chamber, providing a transition metal precursorto the reaction chamber in a vapor phase; and providing an auxiliaryreactant to the reaction chamber in a vapor phase, and providing anitrogen precursor into the reaction chamber in a vapor phase to formtransition metal nitride on the substrate. The transition metalprecursor in the method comprises a transition metal from any of groups4 to 6 of the periodic table of elements. In some embodiments, thetransition metal nitride layer according to the current disclosure has aresistivity of less than about 600 μΩ cm. In some embodiments, thetransition metal nitride layer according to the current disclosure has acarbon content of less than about 20 at. %.

In one aspect, a semiconductor structure comprising transition metalnitride deposited by a cyclic deposition process is disclosed. Themethod comprises providing a substrate in a reaction chamber, providinga transition metal precursor to the reaction chamber in a vapor phaseand providing a nitrogen precursor into the reaction chamber in a vaporphase to form transition metal nitride on the substrate. In the method,the transition metal precursor comprises a transition metal from any ofgroups 4 to 6 of the periodic table of elements. Thus, a semiconductorstructure comprising transition metal nitride deposited according to themethod of the current disclosure is disclosed.

In another aspect, a semiconductor device comprising transition metalnitride deposited by a cyclic deposition process is disclosed. Themethod comprises providing a substrate in a reaction chamber, providinga transition metal precursor to the reaction chamber in a vapor phaseand providing a nitrogen precursor into the reaction chamber in a vaporphase to form transition metal nitride on the substrate. In the method,the transition metal precursor comprises a transition metal from any ofgroups 4 to 6 of the periodic table of elements. Thus, a semiconductordevice comprising transition metal nitride deposited according to themethod of the current disclosure is disclosed.

In yet another aspect, a deposition assembly for depositing transitionmetal nitride-containing material on a substrate is disclosed, Thedeposition assembly comprises one or more reaction chambers constructedand arranged to hold the substrate and a precursor injector systemconstructed and arranged to provide a transition metal precursor, anauxiliary reactant and a nitrogen precursor into the reaction chamber ina vapor phase. The deposition assembly further comprises a precursorvessel constructed and arranged to contain a transition metal precursorcomprising a transition metal from any of groups 4 to 6 of the periodictable of elements and the assembly is constructed and arranged toprovide the transition metal precursor, the auxiliary reactant and thenitrogen precursor via the precursor injector system to the reactionchamber to deposit transition metal nitride-containing material on thesubstrate.

In this disclosure, any two numbers of a variable can constitute aworkable range of the variable, and any ranges indicated may include orexclude the endpoints. Additionally, any values of variables indicated(regardless of whether they are indicated with “about” or not) may referto precise values or approximate values and include equivalents, and mayrefer to average, median, representative, majority, or the like.Further, in this disclosure, the terms “including,” “constituted by” and“having” refer independently to “typically or broadly comprising,”“comprising,” “consisting essentially of,” or “consisting of” in someembodiments. In this disclosure, any defined meanings do not necessarilyexclude ordinary and customary meanings in some embodiments.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the disclosure and constitute a part of thisspecification, illustrate exemplary embodiments, and together with thedescription help to explain the principles of the disclosure. In thedrawings

FIGS. 1A-1D are block diagrams of exemplary embodiments of a methodaccording to the current disclosure.

FIG. 2 is a schematic presentation of a transition metal nitride layerdeposited according to the current disclosure.

FIG. 3 is a schematic presentation of a deposition assembly according tothe current disclosure.

DETAILED DESCRIPTION

The description of exemplary embodiments of methods, structures, devicesand deposition assemblies provided below is merely exemplary and isintended for purposes of illustration only. The following description isnot intended to limit the scope of the disclosure or the claims.Moreover, recitation of multiple embodiments having indicated featuresis not intended to exclude other embodiments having additional featuresor other embodiments incorporating different combinations of the statedfeatures. For example, various embodiments are set forth as exemplaryembodiments and may be recited in the dependent claims. Unless otherwisenoted, the exemplary embodiments or components thereof may be combinedor may be applied separate from each other. The headings providedherein, if any, are for convenience only and do not necessarily affectthe scope or meaning of the claimed invention.

General Process

In an aspect, a method of depositing a transition metalnitride-containing material on a substrate by a cyclic depositionprocess is disclosed. As used herein, the term “transition metalnitride-containing material” may refer to a material comprising at leasta transition metal component and a nitrogen component. The nitrogen mayhave a formal oxidation state of −3.

The transition metal in the transition metal is selected form a groupconsisting of groups 4, 5 and 6 of the periodic table of the elements.Thus, in some embodiments, the transition metal nitride according to thecurrent disclosure is a titanium nitride. In some embodiments, thetransition metal nitride according to the current disclosure is azirconium nitride. In some embodiments, the transition metal nitrideaccording to the current disclosure is a hafnium nitride. In someembodiments, the transition metal nitride according to the currentdisclosure is a vanadium nitride. In some embodiments, the transitionmetal nitride according to the current disclosure is a niobium nitride.In some embodiments, the transition metal nitride according to thecurrent disclosure is a tantalum nitride. In some embodiments, thetransition metal nitride according to the current disclosure is achromium nitride. In some embodiments, the transition metal nitrideaccording to the current disclosure is a molybdenum nitride. In someembodiments, the transition metal nitride according to the currentdisclosure is a tungsten nitride.

Transition Metal Nitride Layer

In some embodiments, transition metal nitride is deposited on asubstrate as a layer. In such embodiments, transition metal nitrideforms a transition metal nitride layer. As used herein, a “transitionmetal nitride layer” can be a material layer that contains transitionmetal and nitrogen, and they are present at least partially astransition metal nitride. In some embodiments, the transition metal andnitrogen are present predominantly as transition metal nitride. Forexample, in some embodiments, at least 30% of the nitrogen in thetransition metal nitride layer is nitride. In some embodiments, at least50% of the nitrogen in the transition metal nitride layer is nitride. Insome embodiments, at least 70% of the nitrogen in the transition metalnitride layer is nitride. In some embodiments, at least 90% of thenitrogen in the transition metal nitride layer is nitride. In someembodiments, at least 95% of the nitrogen in the transition metalnitride layer is nitride.

As used herein, the term “layer” and/or “film” can refer to anycontinuous or non-continuous structure and material, such as materialdeposited by the methods disclosed herein. For example, layer and/orfilm can include two-dimensional materials, three-dimensional materials,nanoparticles or even partial or full molecular layers or partial orfull atomic layers or clusters of atoms and/or molecules. A film orlayer may comprise material or a layer with pinholes, which may be atleast partially continuous. A seed layer may be a non-continuous layerserving to increase the rate of nucleation of another material. However,the seed layer may also be substantially or completely continuous.

Without limiting the current disclosure to any specific theory, in someembodiments it may be possible to produce transition metal nitridelayers with low resistivity. The resistivity of a transition metalnitride layer according to the current disclosure may be less than about600 μΩ cm. In some embodiments, the resistivity of a transition metalnitride layer is less than about 500 μΩ cm, such as about 400 μΩ cm. Insome embodiments, the resistivity of a transition metal nitride layer isless than about 300 μΩ cm, such as 250 μΩ cm. In some embodiments, theresistivity of a transition metal nitride layer is less than about 200μΩ cm, such as 170 μΩ cm.

In some embodiments, a transition metal nitride layer may comprise, forexample, about 60 to about 99 atomic percentage (at. %) transition metaland nitrogen, or about 75 to about 99 at. % transition metal andnitrogen, or about 75 to about 95 at. % transition metal and nitrogen,or about 75 to about 89 at. % transition metal and nitrogen. Atransition metal nitride layer deposited by a method according to thecurrent disclosure may comprise, for example about 80 at. %, about 83at. %, about 85 at. %, about 87 at. %, about 90 at. %, about 95 at. %,about 97 at. %or about 99 at. %transition metal and nitrogen. In someembodiments, a transition metal nitride layer may consist essentiallyof, or consist of transition metal nitride. Layer consisting oftransition metal nitride may include an acceptable amount of impurities,such as oxygen, carbon, chlorine or other halogen, and/or hydrogen thatmay originate from one or more precursors used to deposit the transitionmetal nitride layer. However, in some embodiments, transition metalnitride layer may contain substantially only transition metal andnitrogen, and substantially all the nitrogen is in nitride form. Thus,transition metal layer may comprise, consist essentially of, or consistof transition metal nitride. In some embodiments, the transition metalnitride layer may be a seed layer. A seed layer may be used to enhancethe deposition of another layer. In some embodiments, a transition metalnitride layer is a barrier layer.

In some embodiments, the transition metal nitride layer may compriseless than about 35 at. %, less than about 30 at. %, less than about 20at. %, less than about 10 at. %, less than about 8 at. %, less thanabout 7 at. %, less than about 5 at. %, or less than about 2 at. %oxygen. In some embodiments, the transition metal nitride layer maycomprise less than about 20 at. %, less than about 15 at. %, less thanabout 10 at. %, less than about 8 at. %, less than about 5 at. % or lessthan about 3 at. % carbon.

Substrate

The deposition method according to the current disclosure comprisesproviding a substrate in a reaction chamber. The substrate may be anyunderlying material or materials that can be used to form, or uponwhich, a structure, a device, a circuit, or a layer can be formed. Asubstrate can include a bulk material, such as silicon (e.g.,single-crystal silicon), other Group IV materials, such as germanium, orother semiconductor materials, such as a Group II-VI or Group III-Vsemiconductor materials, and can include one or more layers overlying orunderlying the bulk material. Further, the substrate can include variousfeatures, such as recesses, protrusions, and the like formed within oron at least a portion of a layer of the substrate. For example, asubstrate can include bulk semiconductor material and an insulating ordielectric material layer overlying at least a portion of the bulksemiconductor material. Substrate may include nitrides, for example TiN,oxides, insulating materials, dielectric materials, conductivematerials, metals, such as such as tungsten, ruthenium, molybdenum,cobalt, aluminum or copper, or metallic materials, crystallinematerials, epitaxial, heteroepitaxial, and/or single crystal materials.In some embodiments of the current disclosure, the substrate comprisessilicon. The substrate may comprise other materials, as described above,in addition to silicon. The other materials may form layers.Specifically, the substrate may comprise a partially fabricatedsemiconductor device.

Reaction Chamber

The method of depositing transition metal according to the currentdisclosure comprises providing a substrate in a reaction chamber. Inother words, a substrate is brought into space where the depositionconditions can be controlled. The reaction chamber may be part of acluster tool in which different processes are performed to form anintegrated circuit. In some embodiments, the reaction chamber may be aflow-type reactor, such as a cross-flow reactor. In some embodiments,the reaction chamber may be a showerhead reactor. In some embodiments,the reaction chamber may be a space-divided reactor. In someembodiments, the reaction chamber may be single wafer ALD reactor. Insome embodiments, the reaction chamber may be a high-volumemanufacturing single wafer ALD reactor. In some embodiments, thereaction chamber may be a batch reactor for manufacturing multiplesubstrates simultaneously.

Further, in the method according to the current disclosure, anorganometallic transition metal precursor is provided into the reactionchamber in a vapor phase, and a nitrogen precursor is provided into thereaction chamber in a vapor phase to form a transition metal nitride onthe substrate.

In the method according to the current disclosure, the transition metalprecursor may be in vapor phase when it is in a reaction chamber. Thetransition metal precursor may be partially gaseous or liquid, or evensolid at some points in time prior to being provided in the reactionchamber. In other words, a transition metal precursor may be solid,liquid or gaseous, for example, in a precursor vessel or otherreceptacle before delivery in a reaction chamber. Various means ofbringing the precursor in to gas phase can be applied when delivery intothe reaction chamber is performed. Such means may include, for example,heaters, vaporizers, gas flow or applying lowered pressure, or anycombination thereof. Thus, the method according to the currentdisclosure may comprise heating the transition metal precursor prior toproviding it to the reaction chamber. In some embodiments, transitionmetal precursor is heated to at least 60° C., to at least 100° C., or toat least 110° C., or to at least 120° C. or to at least 130° C. or to atleast 140° C. in the vessel. In some embodiments, the transition metalprecursor is heated to at most 160° C., or to at most 140° C., or to atmost 120° C., or to at most 100° C., or to at most 80° C., or to at most60° C. Also the injector system may be heated to improve the vapor phasedelivery of the transition metal precursor to the reaction chamber.

In this disclosure, “gas” can include material that is a gas at normaltemperature and pressure (NTP), a vaporized solid and/or a vaporizedliquid, and can be constituted by a single gas or a mixture of gases,depending on the context. Transition metal precursor may be provided tothe reaction chamber in gas phase. The term “inert gas” can refer to agas that does not take part in a chemical reaction and/or does notbecome a part of a layer to an appreciable extent. Exemplary inert gasesinclude He and Ar and any combination thereof. In some cases, molecularnitrogen and/or hydrogen can be an inert gas. A gas other than a processgas, i.e., a gas introduced without passing through a precursor injectorsystem, other gas distribution device, or the like, can be used for,e.g., sealing the reaction space, and can include a seal gas.

In the method according to the current disclosure, a nitrogen precursormay be contacted with the substrate comprising a chemisorbed transitionmetal precursor. The conversion of a transition metal precursor totransition metal nitride may take place at the substrate surface. Insome embodiments, the conversion may take place at least partially inthe gas phase. In some embodiments, an auxiliary reactant may becontacted with the substrate comprising a chemisorbed transition metalprecursor. Contacting the substrate comprising the chemisorbedtransition metal precursor with an auxiliary reactant may take placebefore or after contacting the substrate comprising a chemisorbedtransition metal precursor with a nitrogen precursor. Without limitingthe current disclosure to any specific theory, an auxiliary reactant mayform an intermediate species affecting the formation of transition metalnitride on the substrate surface. In some embodiments, the auxiliaryreactant comprises a bond that may be broken to produce an intermediatespecies with a transition metal precursor chemisorbed to the substrate.Without limiting the current disclosure to any specific theory, theauxiliary reactant may form two monoanionic species, both attaching to atransition metal precursor chemisorbed to the substrate, This may changethe formal oxidation state of the transition metal, and lead intorelease of one or more of the groups attached to it. The release maytake place through intermediate steps. In some embodiments, the bondthat may be broken is a bond between a group 14 element and a halogen.In some embodiments, the bond that may be broken is a carbon-halogenbond. In some embodiments, the bond that may be broken is a bond betweentwo halogen atoms. The halogen may be the same or a different element.In some embodiments, the bond that may be broken is a bond between twoatoms of a group 14 element. The group 14 element may be the same or adifferent element. For example, the bond that may be broken may be aC—Br bond, or a C—I bond, or a Br—Br bond, or a I—I bond, or a C—Sibond, or a C—Ge bond, or a Si—Si bond, or a Ge—Ge bond,

Cyclic Deposition Process

In the current disclosure, the deposition process may comprise a cyclicdeposition process, such as an atomic layer deposition (ALD) process ora cyclic chemical vapor deposition (cyclic CVD) process. The term“cyclic deposition process” can refer to the sequential introduction ofprecursor(s) and/or reactant(s) into a reaction chamber to depositmaterial, such as transition metal, on a substrate. Cyclic depositionincludes processing techniques such as atomic layer deposition (ALD),cyclic chemical vapor deposition (cyclic CVD), and hybrid cyclicdeposition processes that include an ALD component and a cyclic CVDcomponent. The process may comprise a purge step between providingprecursors or between providing a precursor and a reactant in thereaction chamber.

The process may comprise one or more cyclic phases. For example, pulsingof transition metal and nitrogen precursor may be repeated. In someembodiments, the process comprises or one or more acyclic phases. Insome embodiments, the deposition process comprises the continuous flowof at least one precursor. In some embodiments, a reactant may becontinuously provided in the reaction chamber. In such an embodiment,the process comprises a continuous flow of a precursor or a reactant. Insome embodiments, one or more of the precursors and/or reactants areprovided in the reaction chamber continuously. In some embodiments,auxiliary reactant may be provided in the reaction chamber continuously.

The term “atomic layer deposition” (ALD) can refer to a vapor depositionprocess in which deposition cycles, such as a plurality of consecutivedeposition cycles, are conducted in a reaction chamber. The term atomiclayer deposition, as used herein, is also meant to include processesdesignated by related terms, such as chemical vapor atomic layerdeposition, when performed with alternating pulses ofprecursor(s)/reactant(s), and optional purge gas(es). Generally, for ALDprocesses, during each cycle, a precursor is introduced to a reactionchamber and is chemisorbed to a deposition surface (e.g., a substratesurface that may include a previously deposited material from a previousALD cycle or other material), forming about a monolayer or sub-monolayerof material that does not readily react with additional precursor (i.e.,a self-limiting reaction). Thereafter, in some cases, another precursoror a reactant may subsequently be introduced into the process chamberfor use in converting the chemisorbed precursor to the desired materialon the deposition surface. The second precursor or a reactant can becapable of further reaction with the precursor. Purging steps may beutilized during one or more cycles, e.g., during each step of eachcycle, to remove any excess precursor from the process chamber and/orremove any excess reactant and/or reaction byproducts from the reactionchamber. Thus, in some embodiments, the cyclic deposition processcomprises purging the reaction chamber after providing a transitionmetal precursor into the reaction chamber. In some embodiments, thecyclic deposition process comprises purging the reaction chamber afterproviding a nitrogen precursor into the reaction chamber. In someembodiments, the cyclic deposition process comprises purging thereaction chamber after providing an auxiliary reactant into the reactionchamber. In some embodiments, the cyclic deposition process comprisespurging the reaction chamber after providing a transition metalprecursor into the reaction chamber, and after providing a nitrogenprecursor into the reaction chamber and providing an auxiliary reactantinto the reaction chamber.

CVD type processes typically involve gas phase reactions between two ormore precursors and/or reactants. The precursor(s) and reactant(s) canbe provided simultaneously to the reaction space or substrate, or inpartially or completely separated pulses. The substrate and/or reactionspace can be heated to promote the reaction between the gaseousprecursor and/or reactants. In some embodiments the precursor(s) andreactant(s) are provided until a layer having a desired thickness isdeposited. In some embodiments, cyclic CVD processes can be used withmultiple cycles to deposit a thin film having a desired thickness. Incyclic CVD processes, the precursors and/or reactants may be provided tothe reaction chamber in pulses that do not overlap, or that partially orcompletely overlap.

In some embodiments, at least one of a transition metal precursor, anitrogen precursor, and an auxiliary reactant is provided to thereaction chamber in pulses. In some embodiments, the transition metalprecursor is supplied in pulses, the nitrogen precursor is supplied inpulses and auxiliary reactant supplied in pulses, and the reactionchamber is purged between consecutive pulses of a precursor or areactant. A duration of providing a transition metal precursor, anitrogen precursor or an auxiliary reactant into the reaction chamber(i.e. reactant or precursor pulse time, respectively) may be, forexample, from about 0.01 s to about 60 s, for example from about 0.01 sto about 5 s, or from about 1 s to about 20 s, or from about 0.5 s toabout 10 s, or from about 5 s to about 15 s, or from about 10 s to about30 s, or from about 10 s to about 60 s, or from about 20 s to about 60s. The duration of a transition metal precursor or a reactant pulse maybe, for example 0.03 s, 0.1 s, 0.5 s, 1 s, 1.5 s, 2 s, 2.5 s, 3 s, 4 s,5 s, 8 s, 10 s, 12 s, 15 s, 25 s, 30 s, 40 s, 50 s or 60 s. In someembodiments, transition metal precursor pulse time may be at least 5seconds, or at least 10 seconds, or at least 20 seconds, or at least 30seconds. In some embodiments, transition metal precursor pulse time maybe at most 5 seconds, or at most 10 seconds or at most 20 seconds, or atmost 30 seconds. In some embodiments, reactant pulse time may be atleast 15 seconds, or at least 30 seconds, or at least 45 seconds, or atleast 60 seconds. In some embodiments, reactant pulse time may be atmost 15 seconds, or at most 30 seconds or at most 45 seconds, or at most60 seconds.

The pulse times for transition metal precursor, nitrogen precursor andauxiliary reactant vary independently according to process in question.The selection of an appropriate pulse time may depend on the substratetopology. For higher aspect ratio structures, longer pulse times may beneeded to obtain sufficient surface saturation in different areas of ahigh aspect ratio structure. Also the selected transition metalprecursor and reactant chemistries may influence suitable pulsing times.For process optimization purposes, shorter pulse times might bepreferred as long as appropriate layer properties can be achieved. Insome embodiments, transition metal precursor pulse time is longer thannitrogen precursor pulse time. In some embodiments, nitrogen precursorpulse time is longer than transition metal precursor pulse time. In someembodiments, transition metal precursor pulse time is the same asnitrogen precursor pulse time. In some embodiments, transition metalprecursor pulse time is longer than auxiliary reactant pulse time. Insome embodiments, nitrogen precursor pulse time is longer than auxiliaryreactant pulse time. In some embodiments, transition metal precursorpulse time is shorter than auxiliary reactant pulse time. In someembodiments, nitrogen precursor pulse time is shorter than auxiliaryreactant pulse time. In some embodiments, transition metal precursorpulse time is the same as auxiliary reactant pulse time. In someembodiments, nitrogen precursor pulse time is the same as auxiliaryreactant pulse time.

In some embodiments, providing a transition metal precursor, a nitrogenprecursor and/or providing an auxiliary reactant into the reactionchamber comprises pulsing the transition metal precursor, the nitrogenprecursor and/or the auxiliary reactant over a substrate. In certainembodiments, pulse times in the range of several minutes may be used forthe transition metal precursor, the nitrogen precursor and/or theauxiliary reactant. In some embodiments, transition metal precursor maybe pulsed more than one time, for example two, three or four times,before a nitrogen precursor is pulsed to the reaction chamber.Similarly, there may be more than one pulse, such as two, three or fourpulses, of a nitrogen precursor or auxiliary reactant before transitionmetal precursor is pulsed (i.e. provided) into the reaction chamber.

A flow rate of the transition metal precursor, the nitrogen precursorand the auxiliary reactant (i.e. transition metal precursor, nitrogenprecursor, or auxiliary reactant flow rate, respectively) may vary fromabout 5 sccm to about 20 slm. The flow rate of the different reactiongases may be selected independently for each gas. During providing atransition metal precursor, nitrogen precursor and/or an auxiliaryreactant into the reaction chamber, a flow rate of the transition metalprecursor, the nitrogen precursor and/or auxiliary reactant may be lessthan 3,000 sccm, or less than 2,000 sccm, or less than 1,000 sccm, orless than 500 sccm, or less than 100 sccm. A transition metal precursorflow rate, a nitrogen precursor flow rate and/or auxiliary reactant flowrate may be, for example, form 500 sccm 1200 sccm, such as 600 sccm, 800sccm or 1000 sccm. In some embodiments, a flow rate of the transitionmetal precursor, the nitrogen precursor and/or the auxiliary reactantinto the reaction chamber is between 50 sccm and 3,000 sccm, or between50 sccm and 2,000 sccm, or between 50 sccm and 1,000 sccm. In someembodiments, a flow rate of the transition metal precursor, the nitrogenprecursor and/or the auxiliary reactant into the reaction chamber isbetween 50 sccm and 900 sccm, or between 50 sccm and 800 sccm or between50 sccm and 500 sccm. In some embodiments, higher flow rates may beutilized. For example, a transition metal precursor flow rate, anitrogen precursor flow rate and/or an auxiliary reactant flow rate maybe 5 slm or higher. In some embodiments, a transition metal precursorflow rate, a nitrogen precursor flow rate and/or auxiliary reactant flowrate may be 10 slm, 12 slm or 15 slm or 20 slm.

Purging

As used herein, the term “purge” may refer to a procedure in which vaporphase precursors and/or vapor phase byproducts are removed from thesubstrate surface for example by evacuating the reaction chamber with avacuum pump and/or by replacing the gas inside a reaction chamber withan inert or substantially inert gas such as argon or nitrogen. Purgingmay be effected between two pulses of gases which react with each other.However, purging may be effected between two pulses of gases that do notreact with each other. For example, a purge, or purging may be providedbetween pulses of two precursors or between a precursor and a reactant.Purging may avoid or at least reduce gas-phase interactions between thetwo gases reacting with each other. It shall be understood that a purgecan be effected either in time or in space, or both. For example in thecase of temporal purges, a purge step can be used e.g. in the temporalsequence of providing a first precursor to a reactor chamber, providinga purge gas to the reactor chamber, and providing a second precursor tothe reactor chamber, wherein the substrate on which a layer is depositeddoes not move. For example in the case of spatial purges, a purge stepcan take the following form: moving a substrate from a first location towhich a first precursor is continually supplied, through a purge gascurtain, to a second location to which a second precursor is continuallysupplied. Purging times may be, for example, from about 0.01 seconds toabout 20 seconds, from about 0.05 s to about 20 s, or from about 1 s toabout 20 s, or from about 0.5 s to about 10 s, or between about 1 s andabout 7 seconds, such as 5 s, 6 s or 8 s. However, other purge times canbe utilized if necessary, such as where highly conformal step coverageover extremely high aspect ratio structures or other structures withcomplex surface morphology is needed, or in specific reactor types, suchas a batch reactor, may be used.

In some embodiments, the method comprises removing excess transitionmetal precursor from the reaction chamber by an inert gas prior toproviding the nitrogen precursor in the reaction chamber. In someembodiments, the reaction chamber is purged between providing atransition metal precursor in a reaction chamber and providing anitrogen precursor in the reaction chamber. In some embodiments, thereaction chamber is purged between providing a transition metalprecursor in a reaction chamber and providing an auxiliary reactant inthe reaction chamber. In some embodiments, the reaction chamber ispurged between providing a nitrogen precursor in a reaction chamber andproviding an auxiliary reactant in the reaction chamber. In someembodiments, the reaction chamber is purged between providing anauxiliary reactant in a reaction chamber and providing a transitionmetal precursor in the reaction chamber. In some embodiments, thereaction chamber is purged between providing an auxiliary reactant in areaction chamber and providing a nitrogen precursor in the reactionchamber. In some embodiments, there is a purge step after everyprecursor and reactant pulse. Thus, the reaction chamber may be purgedalso between two pulses of the same chemistry, such as a transitionmetal precursor ora nitrogen precursor.

Thermal Process

In some embodiments, the cyclic deposition process according to thecurrent disclosure comprises a thermal deposition process. In thermaldeposition, the chemical reactions are promoted by increased temperaturerelevant to ambient temperature. Generally, temperature increaseprovides the energy needed for the formation of transition metalnitride-containing material in the absence of other external energysources, such as plasma, radicals, or other forms of radiation. In someembodiments, the method according to the current disclosure is aplasma-enhanced deposition method, for example PEALD or PECVD.

In some embodiments, transition metal nitride-containing material may bedeposited at a temperature from about 20° C. to about 800° C. Forexample, transition metal nitride-containing material may be depositedat a temperature from about 20° C. to about 450° C., or at a temperaturefrom about 50° C. to about 450° C., or at a temperature from about 50°C. to about 350° C., or at a temperature from about 150° C. to about450° C. In some embodiments of the current disclosure, transition metalnitride-containing material may be deposited at a temperature from about20° C. to about 300° C., or at a temperature from about 200° C. to about450° C. In some embodiments, transition metal nitride-containingmaterial may be deposited at a temperature from about 50° C. to about150° C., or at a temperature from about 250° C. to about 400° C., or ata temperature from about 300° C. to about 450° C. In some embodiments,transition metal nitride-containing material may be deposited at atemperature from about 20° C. to about 200° C., or at a temperature fromabout 150° C. to about 300° C., or at a temperature from about 1500° C.to about 450° C.

For example, transition metal nitride-containing material may bedeposited at a temperature of about 75° C. or about 125° C. or about175° C., or about 200° C., or about 225° C., or about 325° C. or about375° C.

A pressure in a reaction chamber may be selected independently fordifferent process steps. In some embodiments, a first pressure may beused during transition metal precursor pulse, and a second pressure maybe used during reactant pulse. A third or a further pressure may be usedduring purging or other process steps. In some embodiments, a pressurewithin the reaction chamber during the deposition process according tothe current disclosure is less than 760 Torr, or a pressure within thereaction chamber during the deposition process is between 0.1 Torr and760 Torr, or between 1 Torr and 100 Torr, or between 1 Torr and 10 Torr.In some embodiments, a pressure within the reaction chamber during thedeposition process is less than about 0.001 Torr, less than 0.01 Torr,less than 0.1 Torr, less than 1 Torr, less than 10 Torr, less than 50Torr, less than 100 Torr or less than 300 Torr. In some embodiments, apressure within the reaction chamber during at least a part of themethod according to the current disclosure is less than about 0.001Torr, less than 0.01 Torr, less than 0.1 Torr, less than 1 Torr, lessthan 10 Torr or less than 50 Torr, less than 100 Torr or less than 300Torr. For example, in some embodiments, a first pressure may be about0.1 Torr, about 0.5 Torr, about 1 Torr, about 5 Torr, about 10 Torr,about 20 Torr or about 50 Torr. In some embodiments, a second pressureis about 0.1 Torr, about 0.5 Torr, about 1 Torr, about 5 Torr, about 10Torr, about 20 Torr or about 50 Torr.

Transition Metal Precursor

In the method according to the current disclosure, the transition metalprecursor comprises a transition metal from any of groups 4 to 6 of theperiodic table of elements.

The terms “precursor” and “reactant” can refer to molecules (compoundsor molecules comprising a single element) that participate in a chemicalreaction that produces another compound. A precursor typically containsportions that are at least partly incorporated into the compound orelement resulting from the chemical reaction in question. Such aresulting compound or element may be deposited on a substrate. Areactant may me an element or a compound that is not incorporated intothe resulting compound or element to a significant extent. However, areactant may also contribute to the resulting compound or element incertain embodiments.

As used herein, “a transition metal precursor” includes a gas or amaterial that can become gaseous and that can be represented by achemical formula that includes transition metal selected from groups 4(titanium, zirconium, hafnium), 5 (vanadium, niobium, tantalum) or 6(chromium, molybdenum and tungsten) of the periodic table of elements.In some embodiments, the transition metal is in a low oxidation staterelative to the highest stable oxidation state possible for thattransition metal. In some embodiments, the oxidation state of thetransition metal is 3+. In some embodiments, the oxidation state of thetransition metal is 2+. In some embodiments, the oxidation state of thetransition metal is zero.

In some embodiments, the transition metal precursor comprises a group 4transition metal. The transition metal precursor may thus comprisetitanium (Ti). The transition metal precursor may alternatively comprisezirconium (Zr). As another alternative, the transition metal precursormay comprise hafnium (Hf). In some embodiments, the transition metal inthe transition metal precursor is selected from a group consisting oftitanium, zirconium and hafnium. In some embodiments, the transitionmetal in the transition metal precursor is selected from a groupconsisting of titanium and hafnium.

In some embodiments, the transition metal precursor comprises a group 5transition metal. The transition metal precursor may thus comprisevanadium (V), or the transition metal precursor may comprise niobium(Nb), or the transition metal precursor may comprise tantalum (Ta). Insome embodiments, the transition metal in the transition metal precursoris selected from a group consisting of vanadium, niobium and tantalum.In some embodiments, the transition metal in the transition metalprecursor is selected from a group consisting of vanadium and tantalum.

In some embodiments, the transition metal precursor comprises a group 6transition metal. The transition metal precursor may comprise chromium(Cr). The transition metal precursor may comprise molybdenum (Mo). Insome embodiments, the group 6 transition metal in the transition metalprecursor is molybdenum. The transition metal precursor may comprisetungsten (W). In some embodiments, the transition metal in thetransition metal precursor is selected from a group consisting ofchromium, molybdenum and tungsten. In some embodiments, the transitionmetal in the transition metal precursor is selected from a groupconsisting of molybdenum and tungsten.

In some embodiments, transition metal precursor is provided in a mixtureof two or more compounds. In a mixture, the other compounds in additionto the transition metal precursor may be inert compounds or elements. Insome embodiments, transition metal precursor is provided in acomposition. Compositions suitable for use as composition can include atransition metal compound and an effective amount of one or morestabilizing agents. Composition may be a solution or a gas in standardconditions.

In the embodiments of the current disclosure, a transition metalprecursor comprises a transition metal atom and an organic ligand. Insome embodiments, transition metal precursor comprises a metal-organicprecursor comprising a transition metal according to the currentdisclosure. Thus, the transition metal precursor is a metal-organicprecursor. By a metal-organic precursor is herein meant a transitionmetal precursor comprising a metal, such as a group 4-6 transition metalaccording to the current disclosure, and an organic ligand, wherein ametal atom is not directly bonded to a carbon atom. In some embodiments,a metal-organic precursor comprises one transition metal atom, which isnot directly bonded with a carbon atom. In some embodiments, ametal-organic precursor comprises two or more transition metal atoms,none of which is directly bonded to a carbon atom. In some embodiments,a metal-organic precursor comprises two or more transition metal atoms,wherein at least one transition metal atom is not directly bonded to acarbon atom.

In some embodiments, transition metal precursor comprises anorganometallic compound comprising a transition metal according to thecurrent disclosure. Thus, the transition metal precursor is anorganometallic precursor. By an organometallic precursor is herein meanta transition metal precursor comprising a transition metal, such as agroup 4-6 transition metal according to the current disclosure, and anorganic ligand, wherein the transition metal atom is directly bonded toa carbon atom. In embodiments in which an organometallic precursorcomprises two or more transition metal atoms, all of the metal atoms aredirectly bonded with a carbon atom.

In some embodiments, the transition metal precursor comprises only atransition metal atom according to the current disclosure, carbon andhydrogen. In other words, transition metal precursor does not containoxygen, nitrogen or other additional elements. In some embodiments, thetransition metal precursor comprises only molybdenum, carbon andhydrogen. In some embodiments, the transition metal precursor comprisesonly tungsten, carbon and hydrogen. In some embodiments, the transitionmetal precursor comprises only niobium, carbon and hydrogen. In someembodiments, the transition metal precursor comprises only zirconium,carbon and hydrogen.

However, in some embodiments, the metal-organic or organometallicprecursor comprises a transition metal according to the currentdisclosure, carbon, hydrogen and at least one additional element. Theadditional element may be, for example, oxygen, nitrogen or a halogen.In some embodiments, the additional element is not directly bonded tothe metal. Thus, in some embodiments, a transition metal precursor doesnot contain a metal-nitrogen bond. In some embodiments, a transitionmetal precursor does not contain a metal-oxygen bond. In someembodiments, a transition metal precursor does not contain ametal-halogen bond. The at least one additional element in ametal-organic or organometallic precursor may be a ligand. The at leastone additional element may thus be an additional ligand. In someembodiments, the metal-organic or organometallic precursor comprises anadditional ligand, and the ligand is a halide. In some embodiments, themetal-organic or organometallic precursor may comprise at least twoadditional ligands, and one or two of the additional ligands may be ahalide. Each of the additional ligands may be independently selected. Ahalide may be selected from the group consisting of chloro, bromo andiodo. Thus, a ligand may be a halogen atom, selected from the groupconsisting of chlorine, bromine and iodine.

In some embodiments, the transition metal precursor comprises an alkeneligand. In some embodiments, the transition metal precursor comprises api-arene ligand. In some embodiments, the transition metal precursorcomprises a carbonyl ligand. In some embodiments, the transition metalprecursor comprises an additional ligand.

In some embodiments, transition metal precursor comprises at least twoorganic ligands. In some embodiments, transition metal precursorcomprises at least three organic ligands. In some embodiments,transition metal precursor comprises four organic ligands. In someembodiments, transition metal precursor comprises an organic ligand anda hydride ligand. In some embodiments, transition metal precursorcomprises an organic ligand and two or more hydride ligands. In someembodiments, transition metal precursor comprises two organic ligandsand two hydride ligands. In some embodiments, one or more of the organicligands is a hydrocarbon ligand.

In some embodiments, transition metal precursor comprises cyclicportions. For example, the transition metal precursor may comprise abenzene or a cyclopentadienyl ring. In some embodiments, the transitionmetal precursor comprises a benzene or a cyclopentadienyl ring. Thetransition metal precursor may comprise one or more benzene rings. Insome embodiments, the transition metal precursor comprises two benzenerings. One or both benzene rings may comprise hydrocarbon substituents.In some embodiments, each benzene ring of the transition metal precursorcomprises an alkyl substituent. An alkyl substituent may be a methylgroup, an ethyl group, or a linear or branched alkyl group comprisingthree, four, five or six carbon atoms. For example, the alkylsubstituent of the benzene ring may be an n-propyl group or aniso-propyl group. Further, the alkyl substituent may be an n-, iso-,tert- or sec-form of a butyl, pentyl or hexyl moiety. In someembodiments, the transition metal precursor comprises, consistessentially of, or consist of bis(ethylbenzene)transition metal. In someembodiments, a transition metal precursor comprises, consist essentiallyof, or consist of, V(Bz)₂, MoBz₂, CrBz₂, WBz₂, V(EtBz)₂, Mo(EtBz)₂,Cr(EtBz)₂, or W(EtBz)₂, wherein Bz stands for benzene and Et for ethyl.In some embodiments, the transition metal precursor comprisesbis(ethylbenzene)molybdenum. In some embodiments, the transition metalprecursor consists essentially of, or consists ofbis(ethylbenzene)molybdenum

The transition metal precursor may comprise one or more cyclopentadienylgroups. In some embodiments, the transition metal precursor comprisestwo cyclopentadienyl groups. A cyclopentadienyl group may be similarlysubstituted as a benzene group. In other words, one or more of thecyclopentadienyl groups may comprise hydrocarbon substituents. In someembodiments, one or both of the cyclopentadienyl groups has an alkylsubstituent, such as a methyl group, an ethyl group, or a linear orbranched alkyl group comprising three, four, five or six carbon atoms.For example, the alkyl substituent of the cyclopentadienyl group may bean n-propyl group, an iso-propyl group. Further, the alkyl substituentmay be an n-, iso-, tert- or sec-form of a butyl, pentyl or hexylmoiety.

Some examples of transition metal precursors according to the currentdisclosure comprising a cyclopentadienyl moiety are TiCp₂Cl₂, TiCp₂Br₂,TiCp₂, TiCp₂(CO)₂, TiCp₂I₂, TiCp₂H₂, TiCpCl₃, TiCpBr₃, TiCpI₃, HfCp₂Cl₂,HfCp₂Br₂, HfCp₂, HfCp₂(CO)₂, HfCp₂I₂, HfCp₂H₂, HfCpCl₃, HfCpBr₃, HfCpI₃,ZrCp₂Cl₂, ZrCp₂Br₂, ZrCp₂, ZrCp₂(CO)₂, ZrCp₂I₂, ZrCp₂H₂, ZrCpCl₃,ZrCpBr₃, ZrCpI₃, VCp₂Cl₂, VCp₂Br₂, VCp₂I₂, VCp₂, VCp₂(CO)₄, TaCp₂Cl₂,TaCp₂I₂, TaCp₂Br₂, TaCp₂H₂, NbCp₂, NbCp₂H₂, NbCp₂Cl₂, MoCp₂Cl₂, MoCp₂H₂,CrCp₂H₂, CrCp₂Cl₂, WCp₂Cl₂, WCp₂Br₂ and WCp₂I₂.

Some further examples of cyclopentadienyl-containing transition metalprecursors are Ti(iPrCp)₂Cl₂, Ti(iPrCp)₂, Ti(MeCp)₂Cl₂, Ti(MeCp)₂,Ti(EtCp)₂Cl₂, Ti(EtCp)₂, Hf(iPrCp)₂Cl₂, Hf(iPrCp)₂, Hf(MeCp)₂Cl₂,Hf(MeCp)₂, Hf(EtCp)₂Cl₂, Hf(EtCp)₂, Zr(iPrCp)₂Cl₂, Zr(iPrCp)₂,Zr(MeCp)₂Cl₂, Zr(MeCp)₂, Zr(EtCp)₂Cl₂, Zr(EtCp)₂, V(iPrCp)₂Cl₂,V(iPrCp)₂, V(MeCp)₂Cl₂, V(MeCp)₂, V(EtCp)₂Cl₂, V(EtCp)₂, Mo(iPrCp)₂Cl₂,Mo(iPrCp)₂H₂, Mo(EtCp)₂H₂, Cr(MeCp)₂, Cr(EtCp)₂, Cr(iPrCp)₂, Cr(tBuCp)₂,Cr(nBuCp)₂, Cr(Me₅Cp)₂, Cr(Me₄Cp)₂, W(EtCp)₂H₂, W(iPrCp)₂Cl₂ andW(iPrCp)₂H₂. In the formulas, Cp stands for cyclopentadienyl, iPr standsfor isopropyl, Me stands for methyl, Et stands for ethyl, iPr stands foriso-propyl, tBu stands for tert-butyl and nBu stands for n-butyl.

In some embodiments, the transition metal precursor may comprise acarbonyl group-containing ligand. For example, the transition metalprecursor may comprise, consist essentially of, or consist of Mo(CO)₆,Mo(1,3,5-cycloheptatriene)(CO)₃. Additionally, in some embodiments, thetransition metal precursor comprises a nitrosyl group -containingligand. For example, the molybdenum precursor may comprise, consistessentially of, or consist of MoCp(CO)₂(NO).

Nitrogen Precursor

The term nitrogen precursor can refer to a gas or a material that canbecome gaseous and that can be represented by a chemical formula thatincludes nitrogen. In some cases, the chemical formula includes nitrogenand hydrogen. In some cases, the nitrogen precursor does not includediatomic nitrogen.

The nitrogen precursor may be selected from one or more of molecularnitrogen (N2), ammonia (NH₃), hydrazine (NH₂NH₂), a hydrazinederivative, a nitrogen-based plasma and other compounds comprising orconsisting of nitrogen and hydrogen. In some embodiments, the nitrogenprecursor comprises hydrazine. In some embodiments, the nitrogenprecursor consists essentially of, or consists of hydrazine. In someembodiments the nitrogen precursor comprises hydrazine substituted byone or more alkyl or aryl substituents. In some embodiments the nitrogenprecursor consists essentially of, or consists of hydrazine substitutedby one or more alkyl or aryl substituents. In some embodiments, thehydrazine derivative comprises an alkyl-hydrazine including at least oneof: tertbutylhydrazine (C₄H₉N₂H₃), methylhydrazine (CH₃NHNH₂),1,1-dimethylhydrazine ((CH₃)₂NNH₂), 1,2-dimethylhydrazine(CH₃)NHNH(CH₃), ethylhydrazine, 1,1-diethylhydrazine,1-ethyl-1-methylhydrazine, isopropylhydrazine, tert-butyl-hydrazine,phenylhydrazine, 1,1-diphenylhydrazine, 1,2-diphenylhydrazine,N-aminopiperidine, N-aminopyrrole, N-aminopyrrolidine,N-methyl-N-phenylhydrazine, 1-amino-1,2,3,4-tetrahydroquinoline,N-aminopiperazine, 1,1-dibenzylhydrazine, 1,2-dibenzylhydrazine,1-ethyl-1-phenylhydrazine, 1-aminoazepane,1-methyl-1-(m-tolyl)hydrazine, 1-ethyl-1-(p-tolyl)hydrazine,1-aminoimidazole, 1-amino-2,6-dimethylpiperidine, N-aminoaziridine, orazo-tert-butane.

In some embodiments, the nitrogen precursor comprises a plasma, such asNH₃ plasma, N₂ plasma and/or N₂/H₂ plasma. In some embodiments, thenitrogen-based plasma may be generated by the application of RF power toa nitrogen containing gas and the nitrogen-based plasma may compriseatomic nitrogen (N), nitrogen ions, nitrogen radicals, and excitedspecies of nitrogen. In some embodiments, the nitrogen-based plasma mayfurther comprise additional reactive species, such as, by the additionof a further gas.

In some embodiments, the nitrogen precursor comprises only nitrogen andhydrogen. For example, a mixture of nitrogen gas and hydrogen gas may beused. In some embodiments, the nitrogen precursor is a mixture ofgaseous H₂ and N₂. In some embodiments, the nitrogen precursor isselected from a group consisting of NH₃, NH₂NH₂, and mixture of gaseousH2 and N2. In some embodiments, the nitrogen precursor does not includediatomic nitrogen, i.e. the nitrogen precursor is a non-diatomicprecursor. In some embodiments, the nitrogen precursor comprisesammonia. In some embodiments, the nitrogen precursor consistsessentially of, or consists of ammonia. In some embodiments the nitrogenprecursor comprises an alkylamine. In some embodiments the nitrogenprecursor consists essentially of or consists of an alkylamine. Examplesof alkylamines include dimethylamine, n-butylamine and t-butylamine.

Auxiliary Reactant

In some embodiments, the method according to the current disclosurefurther comprises providing an auxiliary reactant to the reactionchamber in a vapor phase. Auxiliary reactant may change the carboncontent of the transition metal nitride-containing material. Forexample, amending the ratio of nitrogen precursor provided into thereaction chamber and the auxiliary reactant provided into the reactionchamber, the carbon content of the deposited material may be regulated.This, in turn, may be used to regulate the work function of thetransition metal nitride layer. In some embodiments, reducing the amountof auxiliary reactant provided into the reaction chamber relative to theamount of nitrogen precursor provided into the reaction chamber maylower the work function of the deposited layer. In some embodiments,providing auxiliary reactant in the reaction chamber may lower theresistivity of the deposited transition metal nitride-containingmaterial. In some embodiments, increasing the amount of the auxiliaryreactant provided into the reaction chamber relative to the nitrogenprecursor may lower the resistivity of the deposited transition metalnitride-containing material.

Si Ge, Sn

In some embodiments of the method according to the current disclosure,auxiliary reactant comprises a group 14 element selected from silicon(Si), germanium (Ge) or tin (Sn). In some embodiments, the auxiliaryreactant comprises a group 14 element selected from a group consistingof Si and Ge. In some embodiments, the auxiliary reactant comprises agroup 14 element selected from a group consisting of Si and Sn. In someembodiments, the auxiliary reactant comprises a group 14 elementselected from a group consisting of Ge and Sn.

In some embodiments, an auxiliary reactant comprises one atom of a group14 element according to the current disclosure. In some embodiments, anauxiliary reactant comprises two atoms of a group 14 element accordingto the current disclosure. The two or more atoms of group 14 element maybe the same or a different element. For example, the auxiliary reactantmay contain two Si atoms, two Ge atoms or two Sn atoms. Alternatively,the auxiliary reactant may comprise a Si atom and a Ge atom, a Si atomand a Sn atom or a Sn atom and a Ge atom. In some embodiments, anauxiliary reactant comprises two atoms of a group 14 element accordingto the current disclosure bonded to each other.

In some embodiments, an auxiliary reactant comprises two atoms of agroup 14 element according to the current disclosure bonded to eachother, and each atom of the group 14 element has a halogen atom attachedto it. The halogen may be, for example, CI, F or I. In some embodiments,an auxiliary reactant comprises two atoms of a group 14 elementaccording to the current disclosure bonded to each other, and each atomof the group 14 element has an alkyl group attached to it. For example,the alkyl group may be a methyl, ethyl, propyl, butyl or pentyl.

In some embodiments, an auxiliary reactant comprises at least one Si—Sibond. In some embodiments, an auxiliary reactant comprises at least oneGe—Ge bond. In some embodiments, an auxiliary reactant comprises atleast one Sn—Sn bond. In some embodiments, an auxiliary reactantcomprises at least one Si—Si bond with a halogen atom attached to eachSi atom. In some embodiments, an auxiliary reactant comprises at leastone Ge—Ge bond with a halogen atom attached to each Ge atom. In someembodiments, an auxiliary reactant comprises at least one Sn—Sn bondwith a halogen atom attached to each Ge atom. In some embodiments, theauxiliary reactant comprises one bond between group 14 elements with ahalogen atom attached to each group 14 element atom.

In some embodiments, the auxiliary reactant comprises an organic groupin addition to the group 14 element. An organic group is a groupcontaining a carbon-hydrogen bond. Thus, the auxiliary reactantcomprises a group 14 element selected from a group consisting of Si, Geand Sn, and an organic group. The auxiliary reactant may comprise ahydrocarbon containing at least one carbon atom. There may be one, two,three or four organic groups in an auxiliary reactant. Each organicgroup may independently contain 1 to 12 carbon atoms. For example, eachorganic group may independently comprise a C1to C4 group (i.e. containfrom one to four carbon atoms), a C1 to C6 group, a C1 to C8 group, aC1-C10 group, a C2 to C12 group, a C2 to C6 group, a C2 to C6 group, ora C4 to C8 group or a C4 to C10 group. Therefore, each organic group mayindependently comprise a C1, C2, C3, C4, C5, C6, C7, C8 or a C10 group.An organic group may comprise an alkyl or an aryl. An organic group maycomprise on or more linear, branched or cyclic alkyl. In someembodiments, an organic group comprises an aryl group. An alkyl or anaryl group may be substituted with one or more functional groups, suchas a halogen, alcohol, amine or benzene.

For example, the organic group may comprise a halogenated methane,ethane, propane, 2-methylpropane, 2,2-dimethylpropane (neopentane),n-butane, 2-methylbutane, 2,2-dimethylbutane, n-pentane,2-methylpantane, 3-methylpentane or an n-hexane. In some embodiments,the auxiliary reactant comprises two halogen atoms. In some furtherembodiments, the at least two halogen atoms of the auxiliary reactantmay be attached to different carbon atoms. The halogen atoms may be thesame halogen, for example bromine, iodine, fluorine or chlorine.Alternatively, the halogens may be different halogens, such as iodineand bromine, bromine and chlorine, chlorine and iodine. In someembodiments, the auxiliary reactant comprises 1,2-dihaloalkane or1,2-dihaloalkene or 1,2-dihaloalkyne or 1,2-dihaloarene, where thehalogens are attached to adjacent carbon atoms.

In some embodiments, an auxiliary reactant has a general Formula (I)R_(a)MX_(b) or R_(c)X_(d)M-MR_(c)X_(d). In Formula (I), a is 0, 1, 2 or3, b is 4-a, c is 0, 1 or 2, d is 3-c, R is an organic group asdescribed above, M is Si, Ge or Sn, and each X is independently anyligand. R may be a hydrocarbon. If a is two or three, or c is two, eachR is selected independently. In some embodiments, each R is selectedfrom alkyls and aryls. In some embodiments, R is an organic group asdescribed above. In some embodiments, R is alkyl or an aryl. Forclarity, X may represent different ligands in one auxiliary reactantspecies. Thus, in some embodiments, an auxiliary reactant may be, forexample SiH₂Br₂, SiH₂I₂ or SiH₂Cl₂.

In some embodiments, X is hydrogen, a substituted or an unsubstitutedalkyl or aryl or a halogen. In some embodiments, X is H. In someembodiments, X is an alkyl or an aryl. In some embodiments, Xis a C1 toC4 alkyl. In some embodiments, X is a substituted alkyl or aryl. In someembodiments, X is a substituted alkyl or aryl, wherein the substituentis same as M. In some embodiments, X is selected from a group consistingof H, Me, Et, nPr, iPr, nBu, tBu, M′Me₃, M′Et₃, M′Pr₃, M′Bu₃, Cl, Br, orI, wherein M′ is same as M.

In some embodiments, an auxiliary reactant has a more specific Formula(II) R_(a)SiX_(b). More specifically, an auxiliary reactant may have aformula R₃SiX, R₂SiX₂, RSiX₃, or SiX4. In Formula (II), a, b, R and Xare as in Formula (I). However, in some embodiments, a silicon atom doesnot comprise four identical substituents. In some embodiments, theauxiliary reactant is not SiH₄. In some embodiments, the auxiliaryreactant is not SiH₂Me₂. In some embodiments, an auxiliary reactant isnot SiH₂Et₂. In some embodiments, auxiliary reactant is not Si₂H₂.

In some embodiments, an auxiliary reactant has a more specific Formula(III) R_(a)GeX_(b). More specifically, an auxiliary reactant may have aformula R₃GeX, R₂GeX₂, RGeX₃, or GeX4. In Formula (III), a, b, R and Xare as in Formula (I). However, in some embodiments, a Ge atom does notcomprise four identical substituents. In some embodiments, the auxiliaryreactant is not GeH₄.

In some embodiments, an auxiliary reactant has a more specific Formula(IV) R_(a)SnX_(b). More specifically, an auxiliary reactant may have aformula R₃SnX, R₂SnX₂, RSnX₃, or SnX4. In Formula (IV), a, b, R and Xare as in Formula (I). However, in some embodiments, a tin atom does notcomprise four identical substituents. In some embodiments, the auxiliaryreactant is not SnH₄.

In some embodiments, the auxiliary reactant comprises a halogen selectedfrom iodine and bromine. In some embodiments, the auxiliary reactantcomprises an alkyl halide. In some embodiments, the auxiliary reactantcomprises an alkyl bromide. In some embodiments the auxiliary reactantcomprises an alkyl iodide. In some embodiments the auxiliary reactantcomprises an aryl halide. In some embodiments the auxiliary reactantcomprises an aryl bromide. In some embodiments the auxiliary reactantcomprises an aryl iodide. In some embodiments the auxiliary reactantcomprises an acyl halide. In some embodiments the auxiliary reactantcomprises an acyl bromide. In some embodiments the auxiliary reactantcomprises an acyl iodide. In some embodiments, the auxiliary reactantcomprises, consists essentially of, or consists of molecular halogen. Insome embodiments, the auxiliary reactant comprises molecular iodine, I₂.In some embodiments, the auxiliary reactant comprises molecular bromine,Br₂. In some embodiments, the auxiliary reactant comprises a compoundcontaining a silicon to halogen bond. In some embodiments, the auxiliaryreactant comprises a compound containing a silicon to bromine bond. Insome embodiments, the auxiliary reactant comprises a compound containinga silicon to iodine bond.

In some embodiments, the auxiliary reactant comprises a halogenatedorganic compound (organohalide), and the halogen is selected from agroup consisting of bromine and iodine. In some embodiments, anorganohalide comprising bromine and/or iodine does not comprise a group14 element. Some auxiliary reactants may comprise both one or more group14 element selected from Si, Ge and Sn and an organohalide group,wherein the halogen is selected from bromine and iodine.

In some embodiments, the organohalide in the auxiliary reactantcomprises two or more halogen atoms. The auxiliary reactant may or maynot comprise a group 14 element. Thus, in some embodiments, an auxiliaryreactant consists of carbon, hydrogen and one or more halogen atomsselected from I and Br. In some embodiments, an auxiliary reactantconsists of carbon, oxygen, hydrogen and one or more halogen atomsselected from I and Br.

In some embodiments, an auxiliary reactant comprises a hydrocarbon thatcontains one bromine or one iodine atom. In some embodiments, anauxiliary reactant comprises a hydrocarbon that contains at least onehalogen atom, each halogen selected independently of bromine and iodine.In some embodiments, an auxiliary reactant comprises a hydrocarbon thatcontains two or more bromine or iodine atoms. In some embodiments, anauxiliary reactant comprises a hydrocarbon where two or more bromine oriodine atoms are bonded to a single carbon atom. In some embodiments theauxiliary reactant comprises a hydrocarbon that contains two or morehalogen atoms, the halogen atoms being selected from bromine and iodine.In some embodiments the auxiliary reactant comprises a hydrocarbon wheretwo or more bromine or iodine atoms are bonded to a single carbon atom.In some embodiments, the auxiliary reactant comprises a hydrocarbon inwhich two or more bromine or iodine atoms are bonded to different carbonatoms. In some embodiments, at least two halogen atoms in the auxiliaryreactant are attached to adjacent carbon atoms of the hydrocarbon. Insome embodiments, said carbon atoms are non-adjacent, i.e. the carbonatoms are not directly bonded to each other. In some embodiments, theauxiliary reactant comprises a 1,2-dihaloalkane or 1,2-dihaloalkene or1,2-dihaloalkyne or 1,2-dihaloarene. In some embodiments, the halogenatoms of the auxiliary reactant are the same halogen. In someembodiments, two halogen atoms of the auxiliary reactant are iodine. Insome embodiments, the two halogen atoms of the auxiliary reactant arebromine. In some embodiments, the auxiliary reactant comprises1,2-diiodoethane. In some embodiments, the auxiliary reactant consistsessentially of, or consists of 1,2-diiodoethane.

In some embodiments, the auxiliary reactant has a general Formula (V)X_(a)R_(b)C— (CX_(c)R“_(d))_(n)—CX_(a)R′b, wherein X is halogen, R, R′and R” are independently H or an alkyl group, a and b are independently1 or 2, so that for each carbon atom a+b=3, n is 0, 1, 2, 3, 4 or 5, andc and d are independently 0, 1 or 2, so that for each carbon atom c+d=2.

In some embodiments, the auxiliary reactant has a general Formula (VI)X_(a)RbC—CX_(a)R′_(b), wherein X is halogen, R and R′ are independentlyH or an alkyl group, a and b are independently 1 or 2, so that for eachcarbon atom a+b=3.

In some embodiments, the method comprises providing a WF modifyingreactant into the reaction chamber. The WF modifying reactant may beused to modify the work function of the transition metal nitride-containing material. In some embodiments, the WF modifying reactantcomprises a thiol. In some embodiments, the WF modifying reactantcomprises a C2 to C10 thiol. In some embodiments, the WF modifyingreactant comprises a C2 to C10 dithiol. In some embodiments, the WFmodifying reactant comprises a C3 to C10 thiol. In some embodiments, theWF modifying reactant comprises a C3 to C10 dithiol. In someembodiments, the WF modifying reactant comprises a C4 to C10 thiol. Insome embodiments, the WF modifying reactant comprises a C4 to C10dithiol. Thus, in some embodiments, the WF modifying reactant comprisesa volatilizable organic compound comprising at least one thiol group.Thus, in some embodiments, the WF modifying reactant comprises avolatilizable organic compound comprising at least two thiol groups. Insome embodiments, the WF modifying reactant comprises two thiol groupsattached to adjacent carbon atoms. In some embodiments, the WF modifyingreactant comprises one thiol group at the end of a carbon chain. In someembodiments, the WF modifying reactant comprises only one thiol group atthe end of a carbon chain. In some embodiments, the WF modifyingreactant comprises two thiol groups at the end of a carbon chain. Thetwo thiol groups at the end of the carbon chain may be attached to asingle carbon atom, or to two last carbon atoms at the end of the carbonchain. In some embodiments, the WF modifying reactant comprises at leastone thiol group and an alkyl. In some embodiments, the WF modifyingreactant consists of at least one thiol group and an alkyl. The alkyl ofthe thiol compound may be linear, branched or cyclic. Examples of thiolcompounds include ethane-1-thiol, propane-1-thiol, butane-1-thiol,pentane-1-thiol, hexane-1-thiol, heptane-1-thiol and octane-1-thiol.Further examples of thiol compounds include ethane-1,2-dithiol,propane-1,2-dithiol, butane-1,2-dithiol, pentane-1,2-dithiol,hexane-1,2-dithiol, heptane-1,2-dithiol and octane-1,2-dithiol. In someembodiments, a thiol compound consisting of one or more thiol groups andan alkyl may reduce the work function of the deposited transition metalnitride layer. The carbon chains may be branched at various positions.For example, in some embodiments, the thiol compound may comprise, forexample, 2-methylpropane-1-thiol, 2-methylbutane-1-thiol,2,2-propane-1-thiol, 2-methylpentane-1-thiol, 5-methylpentane-1-thiol,2,4-dimethyl-pentane-1-thiol, or 2-methyl-heptane-1-thiol. In furtherembodiments, the thiol compound may comprise, for example,2-methylpropane-1,2-dithiol, 2-methylbutane-1,2-dithiol,2,2-propane-1,2-dithiol, 2-methylpentane-1,2-dithiol,5-methylpentane-1,2-dithiol, 2,4-dimethyl-pentane-1,2-dithiol, or2-methyl-heptane-1,2-dithiol. In some embodiments, the thiol compoundmay comprise a nonane or a decane comprising 1 or 2 thiol groups.

In some embodiments, the thiol compound comprises a halogen, such asfluorine. In some embodiments, a thiol compound comprising a halogen,such as fluorine, one or more thiol groups and an alkyl may increase thework function of the deposited transition metal nitride layer. In someembodiments, the thiol compound is fluoroalkylthiol. In someembodiments, the fluoroalkylthiol comprises a C3 to C12, such as C8 toC10 alkyl chain. In some embodiments, the fluoroalkylthiol comprises aC3 to C12, such as C8 to C10 linear alkyl chain. In some embodiments,the thiol compound comprises at least two, or at least three, or atleast six, or at least eight, or at least ten, or at least twelvefluorine atoms. In some embodiments, the thiol compound comprises sixfluorine atoms. In some embodiments, the thiol compound comprises eightfluorine atoms. In some embodiments, the thiol compound comprises tenfluorine atoms. In some embodiments, the thiol compound comprises twelvefluorine atoms. In some embodiments, the thiol compound is3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanethiol. In someembodiments, the thiol compound is3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluoro-1-decanethiol.

In some embodiments, the WF modifying reactant is provided into thereaction chamber in at least deposition cycle during depositing thetransition metal nitride -containing material. In some embodiments, WFmodifying reactant is provided into the reaction chamber after the lastdeposition cycle of the deposition process. In some embodiments, the WFmodifying reactant is provided into the reaction chamber after thedeposition has been completed. Thus, providing the WF modifying reactantmay be used as a post-treatment to modify the work function of thedeposited layer.

In another aspect, a transition metal nitride layer produced by a cyclicdeposition process is disclosed. The method comprises providing asubstrate in a reaction chamber, providing a transition metal precursorto the reaction chamber in a vapor phase; and providing an auxiliaryreactant to the reaction chamber in a vapor phase, and providing anitrogen precursor into the reaction chamber in a vapor phase to formtransition metal nitride on the substrate. The transition metalprecursor in the method comprises a transition metal from any of groups4 to 6 of the periodic table of elements.

In some embodiments, the transition metal nitride layer according to thecurrent disclosure has a resistivity of less than about 600 μΩ cm.

In some embodiments, the transition metal nitride layer according to thecurrent disclosure has a carbon content of less than about 20 at. %. Forexample, the carbon content of a transition metal layer depositedaccording to the current disclosure may be less than 15 at. %. or lessthan 10 at. % or less than 3%.

In one aspect, a semiconductor structure comprising transition metalnitride deposited by a cyclic deposition process is disclosed. Themethod comprises providing a substrate in a reaction chamber, providinga transition metal precursor to the reaction chamber in a vapor phaseand providing a nitrogen precursor into the reaction chamber in a vaporphase to form transition metal nitride on the substrate. In the method,the transition metal precursor comprises a transition metal from any ofgroups 4 to 6 of the periodic table of elements. Thus, a semiconductorstructure comprising transition metal nitride deposited according to themethod of the current disclosure is disclosed.

In another aspect, a semiconductor device comprising transition metalnitride deposited by a cyclic deposition process is disclosed. Themethod comprises providing a substrate in a reaction chamber, providinga transition metal precursor to the reaction chamber in a vapor phaseand providing a nitrogen precursor into the reaction chamber in a vaporphase to form transition metal nitride on the substrate. In the method,the transition metal precursor comprises a transition metal from any ofgroups 4 to 6 of the periodic table of elements. Thus, a semiconductordevice comprising transition metal nitride deposited according to themethod of the current disclosure is disclosed.

In yet another aspect, a deposition assembly for depositing transitionmetal nitride-containing material on a substrate is disclosed, Thedeposition assembly comprises one or more reaction chambers constructedand arranged to hold the substrate and a precursor injector systemconstructed and arranged to provide a transition metal precursor, anauxiliary reactant and a nitrogen precursor into the reaction chamber ina vapor phase. The deposition assembly further comprises a precursorvessel constructed and arranged to contain a transition metal precursorcomprising a transition metal from any of groups 4 to 6 of the periodictable of elements and the assembly is constructed and arranged toprovide the transition metal precursor, the auxiliary reactant and thenitrogen precursor via the precursor injector system to the reactionchamber to deposit transition metal nitride -containing material on thesubstrate.

The disclosure is further explained by the following exemplaryembodiments depicted in the drawings. The illustrations presented hereinare not meant to be actual views of any particular material, structure,device or an apparatus, but are merely schematic representations todescribe embodiments of the current disclosure. It will be appreciatedthat elements in the figures are illustrated for simplicity and clarityand have not necessarily been drawn to scale. For example, thedimensions of some of the elements in the figures may be exaggeratedrelative to other elements to help improve the understanding ofillustrated embodiments of the present disclosure. The structures anddevices depicted in the drawings may contain additional elements anddetails, which may be omitted for clarity.

FIG. 1A is a block diagram of an exemplary embodiment of a method 100 ofdepositing a transition metal nitride-containing material on asubstrate. Method 100 may be used to form a layer comprising transitionmetal nitride, i.e. a transition metal nitride layer. The transitionmetal nitride layer can be used during a formation of a structure or adevice, such as a structure or a device described herein. However,unless otherwise noted, methods described herein are not limited to suchapplications.

In the first phase 102, a substrate is provided into a reaction chamber.A substrate according to the current disclosure may comprise, forexample, an oxide, such as silicon oxide (for example thermal siliconoxide or native silicon oxide), aluminum oxide, or a transition metaloxide, such as hafnium oxide. A substrate may comprise a nitride, suchas silicon nitride or titanium nitride, a metal, such as copper, cobaltor tungsten, chalcogenide material, such as molybdenum sulfide. Thetransition metal nitride according to the current disclosure may bedeposited on said surfaces.

The reaction chamber can form part of an atomic layer deposition (ALD)assembly. The assembly may be a single wafer reactor. Alternatively, thereactor may be a batch reactor. Various phases of method 100 can beperformed within a single reaction chamber or they can be performed inmultiple reaction chambers, such as reaction chambers of a cluster tool.In some embodiments, the method 100 is performed in a single reactionchamber of a cluster tool, but other, preceding or subsequent,manufacturing steps of the structure or device are performed inadditional reaction chambers of the same cluster tool. Optionally, anassembly including the reaction chamber can be provided with a heater toactivate the reactions by elevating the temperature of one or more ofthe substrate and/or the reactants and/or precursors. The transitionmetal nitride-containing material according to the current disclosuremay be deposited in a cross-flow reaction chamber. The transition metalnitride-containing material according to the current disclosure may bedeposited in a cross-flow reaction chamber.

During step 102, the substrate can be brought to a desired temperatureand pressure for performing the method according to the currentdisclosure, i.e. providing precursors and/or reactants into the reactionchamber. A temperature (for example temperature of a substrate or asubstrate support) within a reaction chamber can be, for example, fromabout 50° C. to about 350° C., from about 150° C. to about 400° C., fromabout 200° C. to about 350° C. or from about 200° C. to about 450° C. Inan exemplary embodiment, a temperature of 400° C. at most may be used todeposit molybdenum nitride. The deposition temperature may be limited bythe decomposition of a precursor used in the process, and may thus be,for example 280° C., 320° C., 350° C. or 370° C. In some cases, usingdifferent temperatures for different precursors may be advantageous. Insome embodiments, the reaction chamber comprises a top plate, and thetop plate temperature may be lower than the substrate susceptortemperature. For example, a top plate temperature may be at least 50° C.lower than the susceptor temperature. For example, a top platetemperature may be 50° C., 60° C., 70° C. or 80° C. lower than thesusceptor temperature. In some embodiments, a susceptor temperature maybe at least 300° C., such as about 350° C. or about 370° C.

A pressure within the reaction chamber can be less than 760 Torr, orless than 350 Torr, or less than 100 Torr, or less than 50 Torr, or lessthan 10 Torr. For example, a pressure in the reaction chamber may beabout 400 Torr, about 100 Torr, about 50 Torr, about 20 Torr, about 5Torr, Torr or about 0.1 Torr. Different pressure may be used fordifferent process steps.

Transition metal precursor is provided in the reaction chambercontaining the substrate 104. Without limiting the current disclosure toany specific theory, transition metal precursor may chemisorb on thesubstrate during providing transition metal precursor into the reactionchamber. The duration of providing transition metal precursor into thereaction chamber (transition metal precursor pulse time) may be, forexample, 0.01 s, 0.5 s, 1 s, 1.5 s, 2 s, 4 s, 10 s, 20 s, 35 s, 50 s or60 s. In some embodiments, the duration of providing transition metalprecursor in the reaction chamber (transition metal precursor pulsetime) is may be longer than 5 s or longer than 10 s or longer than 30 s.Alternatively, transition metal purge time may be shorter than 60 s,shorter than 30 s, shorter than 10 s, shorter than 4 s, shorter than 1s., or shorter than 0.5 s. For example, for organometallic transitionmetal precursors comprising aromatic groups, pulse times from about 10to 20 seconds may be suitable.

When nitrogen precursor is provided in the reaction chamber 106, it mayreact with the chemisorbed transition metal precursor, or its derivatespecies, to form transition metal nitride on the substrate. The durationof providing nitrogen precursor in the reaction chamber (nitrogenprecursor pulse time) may be, for example 0.1 s, 0.5 s, 1 s, 3 s, 4 s, 5s, 7 s, 10 s, 11 s, 15 s, 25 s, 30 s, 45 s or 60 s. In some embodiments,the duration of providing nitrogen precursor in the reaction chamber isbe shorter than 60 s, shorter than 40 s, shorter than 20 s, shorter than10 s, shorter than 4 s or about 3 s. In some embodiments, a nitrogenprecursor pulse time may be shorter than 60 s, shorter than 40 s,shorter than 25 s, shorter than 15 s, shorter than 8 s, shorter than 5s, or shorter than 2 s.

In some embodiments, transition metal precursor may be heated beforeproviding it into the reaction chamber. In some embodiments, reactantmay be heated before providing it to the reaction chamber. In someembodiments, the reactant may be held in ambient temperature beforeproviding it to the reaction chamber.

Stages 104 and 106, performed in any order, may form a deposition cycle,resulting in the deposition of transition metal nitride. In someembodiments, the two stages of transition metal nitride deposition,namely providing the transition metal precursor and the reactant in thereaction chamber (104 and 106), may be repeated (loop 108). Suchembodiments contain several deposition cycles. The thickness of thedeposited transition metal nitride-containing material may be regulatedby adjusting the number of deposition cycles. The deposition cycle (loop108) may be repeated until a desired transition metal nitride thicknessis achieved. For example, about 150, 150, 250, 500, 750, 1,000, 1,200,1,500 or 2,000 deposition cycles may be performed.

The amount of transition metal nitride deposited during one cycle(growth per cycle) varies depending on the process conditions, and maybe, for example, from about 0.1 A/cycle to about 5 Å/cycle, 0.3 Å/cycleto about 4.5 Å/cycle, such as from about 0.5 Å/cycle to about 3.5Å/cycle or from about 1.2 Å/cycle to about 3.0 Å/cycle. For example, thegrowth rate may be about 1.0 Å/cycle, 1.2 Å/cycle, 1.4. Å/cycle, 1.6Å/cycle, 1.8 Å/cycle, 2 Å/cycle, 2.2 A/cycle, 2.4 Å/cycle. In someembodiments, growth rate of the transition metal nitride-containinglayer may be, for example from about 0.5 Å/cycle to about 2 Å/cycle, orfrom about 2 Å/cycle to about 5 Å/cycle, Depending on the depositionconditions, deposition cycle numbers etc., transition metalnitride-containing layers of variable thickness may be deposited. Forexample, a transition metal nitride-containing layer may have athickness between approximately 0.5 nm and 60 nm, or between about 1 nmand 50 nm, or between about 0.5 nm and 25 nm, or between about 1 nm and50 nm, or between about 10 nm and 60 nm. A transition metal nitridelayer may have a thickness of, for example, approximately 0.2 mm, 0.3mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5mm, 6 mm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 50 nm,70 nm, 85 nm or 100 nm. The desired thickness may be selected accordingto the application in question.

Transition metal precursor and nitrogen precursor may be provided in thereaction chamber in separate steps (104 and 106).

FIG. 1B illustrates an embodiment according to the current disclosure,where steps 104 and 106 are separate by purge steps 105 and 107. In suchembodiments, a deposition cycle comprises one or more purge steps 103,105. During purge steps, precursor(s) and/or reactant(s) can betemporally separated from each other by inert gases, such as argon (Ar),nitrogen (N₂) or helium (He) and/or a vacuum pressure. The separation oftransition metal precursor and nitrogen precursor may alternatively bespatial. The temperature and/or pressure within a reaction chamberduring phases 102 and 104 can be the same or similar to any of thepressures and temperatures noted above in connection with FIG. 1A. Alsothe repetition of a deposition cycle 108 may be performed similarly tothe embodiment of FIG. 1A.

Purging the reaction chamber 103, 105 may prevent or mitigate gas-phasereactions between a transition metal precursor and a nitrogen precursor,and enable possible self-saturating surface reactions. Surplus chemicalsand reaction byproducts, if any, may be removed from the substratesurface, such as by purging the reaction chamber or by moving thesubstrate, before the substrate is contacted with the next reactivechemical. In some embodiments, however, the substrate may be moved toseparately contact a transition metal precursor and a nitrogenprecursor. Because in some embodiments, the reactions may self-saturate,strict temperature control of the substrates and precise dosage controlof the precursors may not be required. However, the substratetemperature is preferably such that an incident gas species does notcondense into monolayers or multimonolayers nor thermally decompose onthe surface.

The duration of a purge may be, for example 0.1 s, 0.5 s, 1 s, 2 s, 5 s,7 s, 10 s, 15 s, 25 s, 30 s, 45 s or 60 s. The length of the purge maydepend on the processing parameters used during the method, such asprecursors used, chamber pressure, temperature and the like.

When performing the method 100, transition metal nitride is depositedonto the substrate. The deposition process according to the currentdisclosure is a cyclic deposition process, and may include cyclic CVD,ALD, or a hybrid cyclic CVD/ALD process. For example, in someembodiments, the growth rate of a particular ALD process may be lowcompared with a CVD process. One approach to increase the growth ratemay be that of operating at a higher deposition temperature than thattypically employed in an ALD process, resulting in some portion of achemical vapor deposition process, but still taking advantage of thesequential introduction of a transition metal precursor and a nitrogenprecursor. Such a process may be referred to as cyclic CVD. In someembodiments, a cyclic CVD process may comprise the introduction of twoor more precursors into the reaction chamber, wherein there may be atime period of overlap between the two or more precursors in thereaction chamber resulting in both an ALD component of the depositionand a CVD component of the deposition. This is referred to as a hybridprocess. In accordance with further examples, a cyclic depositionprocess may comprise the continuous flow of one precursor or reactant,and the periodic pulsing of the other chemical component into thereaction chamber.

In some embodiments, the transition metal precursor is brought intocontact with a substrate surface 104, excess transition metal precursoris partially or substantially completely removed by an inert gas orvacuum 105, and nitrogen precursor is brought into contact with thesubstrate surface comprising transition metal precursor. Transitionmetal precursor may be brought in to contact with the substrate surfacein one or more pulses 104. In other words, pulsing of the transitionmetal precursor 104 may be repeated. The transition metal precursor onthe substrate surface may react with the nitrogen precursor to formtransition metal nitride on the substrate surface. Also pulsing of thenitrogen precursor 106 may be repeated. In some embodiments, nitrogenprecursor may be provided in the reaction chamber first at phase 106.Thereafter, the reaction chamber may be purged 105 and transition metalprecursor provided in the reaction chamber in one or more pulses 104.

In some embodiments, transition metal nitride layer according to thecurrent disclosure may have a resistivity under about 600 μΩ cm. Thethickness of a layer with said resistivity may be, for example, fromabout 10 nm to about 25 nm.

Resistivity of a transition metal nitride layer may be reduced by usinga post-deposition anneal. Annealing may be performed directly afterdeposition of a transition metal nitride layer, i.e. without additionallayers being deposited. Alternatively, annealing may be performed afteradditional layers have been deposited. A transition metal nitride layermay be capped before annealing. A capping layer may comprise, consistessentially of, or consist of silicon nitride. An annealing temperaturefrom about 320° C. to about 500° C. could be used. For example, anannealing temperature may be 330° C., 350° C., 380° C., 400° C., 430° C.or 450° C. or 470° C. Annealing may be performed in a gas atmospherecomprising, consisting essentially of, or consisting of argon,argon-hydrogen mixture, hydrogen, nitrogen or nitrogen-hydrogen mixture.Duration of annealing may be from about 1 minute to about 60 minutes,for example 5 minutes, 20 minutes, 30 minutes or 45 minutes. Anannealing may be performed at a pressure of 0.05 to 760 Torr. Forexample, a pressure during annealing may be about 1 Torr, about 10 Torr,about 100 Torr or about 500 Torr.

FIG. 1C depicts another embodiment of a method according to the currentdisclosure. In this embodiment, a substrate is provided into a reactionchamber 102, a transition metal precursor is provided into the reactionchamber 104 and a nitrogen precursor is provided into the reactionchamber 106 similarly to the embodiments of FIGS. 1A and 1B. In additionto the two precursors at phases 104 and 106, an auxiliary reactant isprovided into the reaction chamber at phase 110. Without limiting thecurrent disclosure to any specific theory, the auxiliary reactant mayinfluence the cyclic deposition process according to the currentdisclosure by reducing the amount of carbon in the transition metalnitride-containing material.

In embodiments comprising providing an auxiliary reactant into thedeposition chamber 110, the transition metal precursor, the nitrogenprecursor and the auxiliary reactant may be provided in different orderand frequency. In some embodiments, providing transition metal precursor104 and a nitrogen precursor 106 into the reaction chamber may beperformed several times, before an auxiliary reactant is provided intothe reaction chamber 110. Thus, the method comprises a subcycleindicated by the loop 108. For example, the subcycle 108 may beperformed from 2 to 60 times, for example, 5, 10, 15, 20, 25, 30 or 50times, before an auxiliary reactant is provided into the reactionchamber at phase 110.

After an auxiliary reactant is provided into the reaction chamber 110,the process may loop back to providing a nitrogen precursor into thereaction chamber 106 through loop 111, or the process may loop back toproviding a transition metal precursor into the reaction chamber 104through loop 112. The loop 111 of providing a nitrogen precursor intothe reaction chamber 106 and providing an auxiliary reactant into thereaction chamber 110 may be performed once or more. For example loop 111may be performed from 2 to 50 times, for example, 3, 5, 10, 15, 20 or 25times, before the deposition process is either ended, or the process islooped through loo 112 back to providing a transition metal precursorinto the reaction chamber 104.

The process may be performed also by repeating only loop 112. Thus, insome embodiments, a transition metal precursor is provided into thereaction chamber 104, a nitrogen precursor is provided into the reactionchamber 106 and an auxiliary reactant is provided into the reactionchamber 110 and the process is looped back to providing a transitionmetal precursor into the reaction chamber 104. Each of phases 104, 106and 110 may comprise one or more pulses of the precursor or reactant, asthe case may be. The precursors and reactants may be provided into thereaction chamber in a sequential manner. The reaction chamber may bepurged after each precursor and/or reactant pulse, denoted by anasterisk in FIG. 1C. In embodiments comprising only loop 112

A unit cycle of providing a transition metal precursor 104, nitrogenprecursor 106 and auxiliary reactant 110 may be repeated, at least once.The unit cycle may be repeated from 2 to about 500 times, for example10, 20, 40, 80, 100, 150, 250 or 400 times.

In some embodiments, transition metal nitride layer according to thecurrent disclosure may be a molybdenum nitride-containing layer and havea resistivity under about 600 μΩ cm, or under 500 μΩ cm, or under 300 μΩcm, or under 250 μΩ cm, or under 200 μΩ cm, or under 100 μΩ cm. Thethickness of a layer with said resistivity may be, for example, fromabout 10 nm to about 20 nm, or under 10 nm.

FIG. 1D illustrates an embodiment according to the current disclosure inwhich the process comprises providing an auxiliary reactant into thereaction chamber 110 after providing a transition metal precursor intothe reaction chamber 104. For example, a substrate comprising thermaloxide may be provided into a reaction chamber at phase 102, and heatedto a temperature of 350° C. Thereafter, a transition metal precursor,such as a molybdenum precursor comprising aromatic ligands may beprovided into the reaction chamber for 10 to 20 seconds, at phase 104.Then, the reaction chamber may be purged for 3 to 10 seconds, and anauxiliary reactant comprising a halogenated hydrocarbon may be providedinto the reaction chamber 110. The auxiliary reactant pulse time may befrom about 1 second to about 15 seconds, after which the reactionchamber may be purged again for 3 to 10 seconds. Then, at phase 106, anitrogen precursor, comprising, for example, only hydrogen and nitrogen,such as NH₃ or hydrazine, may be provided into the reaction chamber. Thetemperature during providing the nitrogen precursor into the reactionchamber may be above 300° C., for example to 320° C. to 350° C. Thepulse time for the nitrogen precursor may be 2 to 8 seconds. Then, thereaction chamber may be purged, and a new deposition unit cycle isstarted by looping 112 to providing a transition metal precursor 102again. The deposition process may comprise 50 to 100 unit cycles.

For clarity, the order of phases depicted in FIG. 1 , panels A to D, isexemplary only, and the order of the precursors and reactants, as wellas the loop repetitions may be selected according to the specificembodiment at hand. Specifically, in some embodiments, providing anitrogen precursor 106 in the beginning of the process may be beneficialfor the material layer growth.

The properties of the transition metal nitride-containing materialdepend on the deposition parameters, such as the precursors andreactants, cycling scheme, and temperature during deposition. Forexample, for molybdenum nitride, a carbon content of 10 at. % or less,for example about 5 at-% or about 7 at. % may be achieved.

The ratio of nitrogen to transition metal in the deposited material mayvary. In some embodiments, the nitrogen to metal ratio may be about 0.7to 1.0. However, in some embodiments, the nitrogen to metal ratio may beabout 0.5, or about 0.3, meaning that the material may have a higheramount of metal compared to nitrogen. The higher metal content relativeto nitrogen may correlate with lowered carbon content.

FIG. 2 illustrates an exemplary structure, or a portion of a device 200in accordance with the disclosure. Portion of a device or structure 200includes a substrate 202, a transition metal nitride layer 204, and anoptional intermediate layer 206 in between (e.g., in contact with one orboth) substrate 202 and transition metal nitride layer 204. Substrate202 can be or include any of the substrate material described herein,such as a dielectric or insulating layer. By way of example, dielectricor insulating layer can be high-k material, such as, for example, ametallic oxide. In some embodiments, the high-k material has adielectric constant higher than the dielectric constant of siliconoxide. Exemplary high-k materials include one or more of hafnium oxide(HfO₂), tantalum oxide (Ta₂O₅), zirconium oxide (ZrO₂), titanium oxide(TiO₂), hafnium silicate (HfSiOx), aluminum oxide (Al₂O₃), lanthanumoxide (La₂O₃), titanium nitride, and mixtures/laminates comprising oneor more such layers. Alternatively, substrate material may comprise ametal, such as Cu, Co, W, or Mo.

Transition metal nitride layer 204 can be formed according to a methoddescribed herein. In embodiments in which an intermediate layer 206, isformed, the intermediate layer 206 may be formed using a cyclicdeposition process. In some embodiments, transition metal nitride layer204 can comprise predominantly, such as at least 50 at. %, at least 70at. %, at least 90 at. % or at least 95 at. %, transition metal andnitride, such as molybdenum nitride, pr tungsten nitride or niobiumnitride. In some embodiments, a transition metal nitride layer may bedeposited directly on the substrate. In such embodiments, there is nointermediate layer. As a further alternative, the structure or a deviceaccording to the current disclosure may comprise more than one layerbetween substrate and transition metal nitride layer.

FIG. 3 illustrates a deposition assembly 300 according to the currentdisclosure in a schematic manner. Deposition assembly 300 can be used toperform a method as described herein and/or to form a structure or adevice, or a portion thereof as described herein.

In the illustrated example, deposition assembly 300 includes one or morereaction chambers 302, a precursor injector system 301, a transitionmetal precursor vessel 304, nitrogen precursor vessel 306, an auxiliaryreactant source 308, an exhaust source 310, and a controller 312. Thedeposition assembly 300 may comprise one or more additional gas sources(not shown), such as an inert gas source, a carrier gas source and/or apurge gas source.

Reaction chamber 302 can include any suitable reaction chamber, such asan ALD or CVD reaction chamber as described herein.

The transition metal precursor vessel 304 can include a vessel and oneor more transition metal precursors as described herein—alone or mixedwith one or more carrier (e.g., inert) gases. Nitrogen precursor vessel306 can include a vessel and one or more nitrogen precursors asdescribed herein—alone or mixed with one or more carrier gases.Auxiliary reactant source 308 can include an auxiliary reactant, or aprecursor thereof as described herein. Although illustrated with threesource vessels 304-308, deposition assembly 300 can include any suitablenumber of source vessels. Source vessels 304-308 can be coupled toreaction chamber 302 via lines 314-318, which can each include flowcontrollers, valves, heaters, and the like. In some embodiments, thetransition metal precursor in the transition metal precursor vessel 304,the nitrogen precursor in the nitrogen precursor vessel 306 and/or theauxiliary reactant in the auxiliary reactant vessel 308 may be heated.In some embodiments, a vessel is heated so that a precursor or areactant reaches a temperature between about 30° C. and about 160° C.,such as between about 100° C. and about 145° C., for example 85° C.,100° C., 110° C., 120° C., 130° C. or 140° C. Each vessel may be heatedto a different temperature, according to the precursor or reactantproperties, such as thermal stability and volatility.

Exhaust source 310 can include one or more vacuum pumps.

Controller 312 includes electronic circuitry and software to selectivelyoperate valves, manifolds, heaters, pumps and other components includedin the deposition assembly 300. Such circuitry and components operate tointroduce precursors, reactants and purge gases from the respectivesources. Controller 312 can control timing of gas pulse sequences,temperature of the substrate and/or reaction chamber 302, pressurewithin the reaction chamber 302, and various other operations to provideproper operation of the deposition assembly 300. Controller 312 caninclude control software to electrically or pneumatically control valvesto control flow of precursors, reactants and purge gases into and out ofthe reaction chamber 302. Controller 312 can include modules such as asoftware or hardware component, which performs certain tasks. A modulemay be configured to reside on the addressable storage medium of thecontrol system and be configured to execute one or more processes.

Other configurations of deposition assembly 300 are possible, includingdifferent numbers and kinds of precursor and reactant sources. Further,it will be appreciated that there are many arrangements of valves,conduits, precursor sources, and auxiliary reactant sources that may beused to accomplish the goal of selectively and in coordinated mannerfeeding gases into reaction chamber 302. Further, as a schematicrepresentation of an deposition assembly, many components have beenomitted for simplicity of illustration, and such components may include,for example, various valves, manifolds, purifiers, heaters, containers,vents, and/or bypasses.

During operation of deposition assembly 300, substrates, such assemiconductor wafers (not illustrated), are transferred from, e.g., asubstrate handling system to reaction chamber 302. Once substrate(s) aretransferred to reaction chamber 302, one or more gases from gas sources,such as precursors, reactants, carrier gases, and/or purge gases, areintroduced into reaction chamber 302.

In some embodiments, the transition metal precursor is supplied inpulses, auxiliary reactant supplied in pulses and the reaction chamberis purged between consecutive pulses of transition metal precursor andauxiliary reactant.

The example embodiments of the disclosure described above do not limitthe scope of the invention, since these embodiments are merely examplesof the embodiments of the invention, which is defined by the appendedclaims and their legal equivalents. Any equivalent embodiments areintended to be within the scope of this invention. Various modificationsof the disclosure, in addition to those shown and described herein, suchas alternative useful combinations of the elements described, may becomeapparent to those skilled in the art from the description. Suchmodifications and embodiments are also intended to fall within the scopeof the appended claims.

1. A method of depositing a transition metal nitride-containing materialon a substrate by a cyclic deposition process, the method comprisingproviding a substrate in a reaction chamber; providing an organometallictransition metal precursor to the reaction chamber in a vapor phase; andproviding a nitrogen precursor into the reaction chamber in a vaporphase to form a transition metal nitride on the substrate; wherein thetransition metal precursor comprises a transition metal from any ofgroups 4 to 6 of the periodic table of elements.
 2. The method of claim1, wherein the transition metal precursor comprises a group 6 transitionmetal.
 3. The method of claim 2, wherein the group 6 transition metal isselected from molybdenum and tungsten.
 4. The method of claim 2, whereinthe group 6 transition metal is molybdenum.
 5. The method of claim 4,wherein the transition metal precursor comprises only molybdenum, carbonand hydrogen.
 6. The method of claim 5, wherein the transition metalprecursor comprises a benzene or a cyclopentadienyl group.
 7. The methodof claim 1, wherein the nitrogen precursor comprises only nitrogen andhydrogen.
 8. The method of claim 1, wherein the nitrogen precursor isselected from a group consisting of NH₃, NH₂NH₂, and mixture of gaseousH₂ and N₂.
 9. The method of claim 1 further comprising providing anauxiliary reactant to the reaction chamber in a vapor phase.
 10. Themethod of claim 9, wherein the auxiliary reactant comprises a halogenselected from a group consisting of bromine and iodine.
 11. The methodof claim 10, wherein the auxiliary reactant comprises a halogenatedhydrocarbon.
 12. The method of claim 11, wherein the auxiliary reactantcomprises two or more halogen atoms.
 13. The method of claim 12, whereinat least two halogen atoms being attached to different carbon atoms. 14.The method of claim 13, wherein two of the halogen atoms in theauxiliary reactant are attached to adjacent carbon atoms of a carbonchain.
 15. The method of claim 14, wherein the auxiliary reactantcomprises a 1,2-dihaloalkane or 1,2-dihaloalkene or 1,2-dihaloalkyne or1,2-dihaloarene.
 16. The method of claim 12, wherein the two halogenatoms of the auxiliary reactant are the same halogen.
 17. The method ofclaim 16, wherein the auxiliary reactant comprises 1,2-diiodoethane. 18.The method of claim 9, wherein the auxiliary reactant is used toregulate the resistivity of the deposited transition metal nitridematerial.
 19. A transition metal nitride layer produced by a cyclicdeposition process comprising providing a substrate in a reactionchamber; providing a transition metal precursor to the reaction chamberin a vapor phase; and providing an auxiliary reactant to the reactionchamber in a vapor phase providing a nitrogen precursor into thereaction chamber in a vapor phase to form transition metal nitride onthe substrate; wherein the transition metal precursor comprises atransition metal from any of groups 4 to 6 of the periodic table ofelements.
 20. The layer of claim 19 having a resistivity of less thanabout 600 μΩ cm.
 21. The layer of claim 19 having a carbon content ofless than about 20 at. %.
 22. A deposition assembly for depositingtransition metal nitride -containing material on a substrate comprising:one or more reaction chambers constructed and arranged to hold thesubstrate; a precursor injector system constructed and arranged toprovide a transition metal precursor, an auxiliary reactant and anitrogen precursor into the reaction chamber in a vapor phase; whereinthe deposition assembly comprises a precursor vessel constructed andarranged to contain a transition metal precursor comprising a transitionmetal from any of groups 4 to 6 of the periodic table of elements; andthe assembly is constructed and arranged to provide the transition metalprecursor, the auxiliary reactant and the nitrogen precursor via theprecursor injector system to the reaction chamber to deposit transitionmetal nitride -containing material on the substrate.